package com.example.msdksample.utils

import android.util.Log

class Logger(private val tag: String) {
    fun info(message: String) {
        Log.i(tag, message)
    }

    fun error(message: String, throwable: Throwable? = null) {
        if (throwable != null) {
            Log.e(tag, message, throwable)
        } else {
            Log.e(tag, message)
        }
    }

    fun debug(message: String) {
        Log.d(tag, message)
    }

    fun warn(message: String) {
        Log.w(tag, message)
    }
}

package com.example.msdksample.activity

import android.content.BroadcastReceiver
import android.content.Context
import android.content.Intent
import android.content.IntentFilter
import android.content.pm.PackageManager
import android.os.Build
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.TextView
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import com.example.msdksample.MyApplication
import com.example.msdksample.R
import com.google.android.material.snackbar.Snackbar

class MainActivity : AppCompatActivity() {

    private lateinit var tvAppActivation: TextView
    private lateinit var btnFlightController: Button

    // Use enum for better type safety
    private enum class ActivationState {
        ACTIVATED,
        NOT_ACTIVATED
    }

    private var appActivationState: ActivationState = ActivationState.NOT_ACTIVATED

    // BroadcastReceiver to monitor application registration and product connection
    private val registerReceiver = object : BroadcastReceiver() {
        override fun onReceive(context: Context, intent: Intent) {
            when (intent.action) {
                MyApplication.REGISTER_SUCCESS -> {
                    appActivationState = ActivationState.ACTIVATED
                    updateActivationUI()
                    showMessage(getString(R.string.register_success))
                }
                MyApplication.REGISTER_FAILURE -> {
                    val errorMessage = intent.getStringExtra("error_message") ?: getString(R.string.unknown_error)
                    appActivationState = ActivationState.NOT_ACTIVATED
                    updateActivationUI()
                    showMessage(getString(R.string.register_failure, errorMessage))
                }
                MyApplication.PRODUCT_CONNECT -> {
                    showMessage(getString(R.string.product_connect))
                }
                MyApplication.PRODUCT_DISCONNECT -> {
                    showMessage(getString(R.string.product_disconnect))
                }
                MyApplication.PRODUCT_CHANGED -> {
                    showMessage(getString(R.string.product_changed))
                }
            }
        }
    }

    private var isReceiverRegistered = false

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        initViews()
        checkAndRequestPermissions()
    }

    private fun initViews() {
        tvAppActivation = findViewById(R.id.tv_status_application)
        btnFlightController = findViewById(R.id.btn_flight_controller)

        btnFlightController.setOnClickListener {
            if (appActivationState == ActivationState.ACTIVATED) {
                val intent = Intent(this, FlightActivity::class.java)
                startActivity(intent)
            } else {
                showMessage(getString(R.string.app_not_activated))
            }
        }

        updateActivationUI()
    }

    private fun updateActivationUI() {
        val statusText = when (appActivationState) {
            ActivationState.ACTIVATED -> getString(R.string.activation_status_activated)
            ActivationState.NOT_ACTIVATED -> getString(R.string.activation_status_not_activated)
        }
        tvAppActivation.text = getString(R.string.activation_status_label, statusText)
    }

    override fun onStart() {
        super.onStart()
        registerBroadcastReceiver()
    }

    override fun onStop() {
        unregisterBroadcastReceiver()
        super.onStop()
    }

    private fun registerBroadcastReceiver() {
        if (!isReceiverRegistered) {
            val filter = IntentFilter().apply {
                addAction(MyApplication.REGISTER_SUCCESS)
                addAction(MyApplication.REGISTER_FAILURE)
                addAction(MyApplication.PRODUCT_CONNECT)
                addAction(MyApplication.PRODUCT_DISCONNECT)
                addAction(MyApplication.PRODUCT_CHANGED)
            }

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
                registerReceiver(registerReceiver, filter, Context.RECEIVER_NOT_EXPORTED)
            } else {
                registerReceiver(registerReceiver, filter)
            }

            isReceiverRegistered = true
        }
    }

    private fun unregisterBroadcastReceiver() {
        if (isReceiverRegistered) {
            try {
                unregisterReceiver(registerReceiver)
                isReceiverRegistered = false
            } catch (e: IllegalArgumentException) {
                // Receiver was already unregistered
            }
        }
    }

    /* Permission Handling */

    private fun getRequiredPermissions(): Array<String> {
        val basePermissions = mutableListOf(
            android.Manifest.permission.RECORD_AUDIO,
            android.Manifest.permission.INTERNET,
            android.Manifest.permission.CHANGE_WIFI_STATE,
            android.Manifest.permission.ACCESS_WIFI_STATE,
            android.Manifest.permission.ACCESS_NETWORK_STATE,
            android.Manifest.permission.CAMERA,
            android.Manifest.permission.ACCESS_COARSE_LOCATION,
            android.Manifest.permission.ACCESS_FINE_LOCATION
        )

        // Only add storage permissions for older Android versions
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU) {
            basePermissions.add(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
            basePermissions.add(android.Manifest.permission.READ_EXTERNAL_STORAGE)
        }

        return basePermissions.toTypedArray()
    }

    private fun checkAndRequestPermissions() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (!hasAllPermissions()) {
                requestAllPermissions()
            } else {
                proceedWithAppFunctionality()
            }
        } else {
            proceedWithAppFunctionality()
        }
    }

    private fun hasAllPermissions(): Boolean {
        return getRequiredPermissions().all {
            ContextCompat.checkSelfPermission(this, it) == PackageManager.PERMISSION_GRANTED
        }
    }

    private fun requestAllPermissions() {
        ActivityCompat.requestPermissions(this, getRequiredPermissions(), PERMISSIONS_REQUEST_CODE)
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)

        if (requestCode == PERMISSIONS_REQUEST_CODE) {
            if (grantResults.isNotEmpty() && grantResults.all { it == PackageManager.PERMISSION_GRANTED }) {
                proceedWithAppFunctionality()
            } else {
                showMessage(getString(R.string.permissions_required))
            }
        }
    }

    private fun proceedWithAppFunctionality() {
        showMessage(getString(R.string.permissions_granted))
    }

    private fun showMessage(message: String) {
        // Use Snackbar instead of Toast for better UX
        Snackbar.make(
            findViewById(android.R.id.content),
            message,
            Snackbar.LENGTH_SHORT
        ).show()
    }

    companion object {
        private const val PERMISSIONS_REQUEST_CODE = 102
    }
}

编程之本：变量和函数

变量

Kotlin 中定义一个变量，只允许在变量前声明两种关键字：val和var。

背景

单位买了一个手持的蓝牙 RTK 终端，通过蓝牙可以获取到设备的差分定位信息。

Android

之前的实例一，通过点击按钮实现起飞。而我这边最终的需求是通过点击网页上的按钮来控制无人机的起飞降落。

由于大疆新的无人机采用Mobile SDK 5.x版本(Kotlin)，而之前学习的版本是4.x(Java)，并且大疆对于5.x版本的文档写的实在不怎么样(相比4.x来说)，所以从新记录一下。

The lateinit keyword in Kotlin is used to declare(声明) a property that will be initialized later. It allows you to avoid(避免) null checks or the use of the null type for properties that you are certain will be initialized before use, but for some reason, you can't initialize them immediately(立即) at declaration.

首先在 AndroidManifest.xml 中添加需要的权限

由于大疆 Mobile SDK 5 将 APP 注册等逻辑放到了 MyApplication 中，但是我还是想在 MainActivity 接收注册成功或失败等消息，所以使用 BroadcastReceiver 来广播消息

Q: Please play a senior Android development engineer to help me solve some problems.

手机开启USB调试后，连上电脑，在Terminal中输入命令：

1、Android Setting Tools 下找到 SpotBugs
2、General 中 Compole affected files before analyze 前面勾选去除

可以使用Java里的单例模式把 Activity 的 context 暴露出来。

本文参考：A Guide to NanoHTTPD

因为公司项目的原因，不得不开始学习Java和Android开发，好在使用Java就能开发Android。